This invention relates to improvements in a method for collecting a saliva sample from human subjects. More particularly, the invention provides indication of the collection of a minimum saliva sample amount as well as providing verification that the sample collected is saliva. The indicator further serves to locate the saliva and to show the sample was properly applied to an absorbent after the saliva has been dried for shipping to a laboratory for HIV antibody testing or drug abuse testing or other viral or bacterial antibody testing, or testing for other analytes of interest.
In collecting body fluid samples, and in particular human body fluid samples, it is at times necessary to collect samples in the field or outside of a controlled collection environment. Two such cases are immediately evident, that of law enforcement sample collection for evidentiary purposes and the collection of samples by the health insurance industry for health status determinations on prospective insurance purchasers.
In law enforcement sample collection of human body fluid samples, the collection of saliva is potentially useful as a superior indicator of blood alcohol levels in contrast to simple "breathalizer" types of testing. Saliva samples can be saved for future confirmation of the original test results whereas the "breathalizer" tests cannot. For the health and life insurance industry saliva testing is useful as a matter of convenience for the individual seeking insurance. When the sample collection for testing for preexisting conditions can be conducted at their home or within their work site, inconvenience is minimized and there is less resistance to testing.
In the insurance industry it has become common practice to send out a medical on-site examiner and have the fluid sample--saliva--collected at a location most convenient for the subject desiring insurance. Heretofore on-site examiners have collected saliva by having individual expectorate into a container and then adding an anti-bacterial agent to the saliva and shipping it into the laboratory for testing or by collecting a sample of saliva on a swab and then plunging the swab into an anti-bacterial agent for shipment into the laboratory.
Inherent in such "on-site" sample collection situations is that subsequent transport of the sample to a testing laboratory is required. In many cases it is convenient, as well as necessary, to ship the sample to the laboratory by mail or courier in order to minimize the number of laboratory operations. In such cases it is beneficial if the sample can be reduced to a solid phase or at least minimized in volume. As a result it has recently been found advantageous to ship body fluid samples, blood in particular, as a dried spot on an absorbent matrix. In this manner the sample volume is reduced and the sample weight commensurately reduced by evaporation of the fluid component.
Conveyance of these physiological fluid samples to the laboratory often occurs under poor conditions and the use of public and private mail delivery or couriers to transport such samples increases the potential for careless handling. Damaged and leaking fluid samples may alarm or endanger courier or mail system workers who contact the damaged and leaking packages of fluid physiological materials. Thus it is of substantial benefit when the fluid component can be reduced or eliminated in such samples.
However, the application of the fluid sample to an absorbent upon which the sample can be dried causes certain problems in the case of saliva. Unlike the on-site examiner the receiving laboratory does not have the advantage of actual observation of the subject. Upon receiving an absorbent upon which a saliva sample has dried, the laboratory must be able to locate the saliva thereon (saliva being invisible unlike blood), determine that a sufficient quantity of the sample has been obtained to perform the tests to be conducted, and verify that the dried sample is, in fact, saliva and not another body fluid or a fake specimen. Once the sample is dried it may be easily transported to a laboratory where a wide range of tests may be performed on the sample.
A dried saliva spot on an absorbent may be used for determining drug use such as cocaine and may also be used for analyzing the health status of the potential insured for HIV antibodies or analytes of interest. The utility of saliva as a testing medium is a direct result of its formation in the body. Saliva is formed in the mouth by the salivary glands of the oral cavity and adjacent areas. The salivary glands consist of two parotid, submandibular and sublingual glands in addition to the labial and lingual glands as well as the small mucous glands of the soft and hard pallet. The daily saliva output is between 500 and 1,500 milliliters. This flow may be affected by various factors including age, sex, time of day, time of year, nutritional state and emotional state of the individual.
The main constituents of saliva are proteins, sodium, potassium, calcium, magnesium, chloride, bicarbonate, and inorganic phosphate. However, as the salivary gland ducts are separated from the human blood circulation by only a layer of epithelial cells many constituents of the blood are passed into the saliva. While most drugs and blood constituents seem to enter the saliva by diffusion across the epithelial cell lipid membrane, it is also possible that there is some active secretion into the saliva of drugs such as penicillin and lithium.
It has been confirmed that intravenous use of cocaine in addition to oral or intra-nasal administrations of cocaine may be determined from saliva. Recently, there has been interest in determining through saliva testing the presence of human immuno-deficiency virus (HIV) antibodies to assist insurance companies in screening out risks to business prior to offering contracts for health and life insurance.
Generally, samples of saliva for these purposes have been obtained by having the subject expectorate into a container. This is assisted by having or by having the subject suck or chew onto a washed rubber band, a piece of paraffin wax, chewing gum or a strip of citric acid-impregnated filter paper and then having the subject expectorate into a container or allowing the saliva to be absorbed onto an absorbent paper or sponge.
These saliva collection techniques, however, may be considered less than optimal for use in a business office situation where the form of collection may be obtrusive and out of keeping with the office environment. In addition, the sample must then be transported back to the testing laboratory and if the laboratory is some distance from the sample gathering location, the inconvenience and difficulty of shipping a body fluid sample is then incurred.
One avenue around these difficulties has been to allow the subject to place an absorbent swab or paper into the mouth and allow the absorbent material to become saturated with saliva within a set time. However, this presents the problem that it is difficult to determine the degree of saturation of the swab and if a number of saliva samples are being concurrently taken, it may not be possible for the on-site examiner to visually observe each subject and thereby personally witness and ascertain that it is saliva which has been absorbed onto the paper.
More importantly, due to the nature of the absorbent paper, it may be difficult for the on-site examiner to determine that adequate sample has been placed on the absorbent to allow proper testing. In this event it is necessary to return to the subject at a later date to collect an additional sample which is not only inconvenient but adds additional expense to the determination being made and may raise questions as to the competence of the company requesting the test, the competency of the on-site examiner, as well as the health of the subject.
Therefore, it is an object of the present invention to provide a method for field saliva sampling which will avoid the above debilities of the present methods of saliva sampling.
Another object is to provide a method for obtaining a saliva sample and determining as the sample is taken that an adequate sample has been obtained.
Yet another object of the present invention is to provide a field saliva sample collection method which can immediately verify that the sample obtained is in fact saliva.
Another object of the present invention is to provide a method for saliva sample taking which will at once indicate to the sample collector that a sufficient sample for testing has been collected and that the collected sample is in fact saliva.
Yet another object of the present invention is to provide a rapid and convenient method for saliva sample collection which can be conveniently and easily stored for law enforcement evidentiary purposes,
It is yet another object of the present invention to provide a method for saliva sample collection which can be conveniently and easily shipped from one location to another.
Yet another object of the invention is to provide a method in which the area of application of a clear fluid sample may be observed after the sample is dried.
Yet another object of the invention is to provide a method that allows determination that the proper sample amount has been applied at the time of sampling as well as after the sample has been allowed to dry.
Yet another object of the invention is to provide a method which protects technical personnel working with a dried clear fluid sample by making apparent the location of the sample after it is dried.
Another object of the invention is to provide a method that indicates that the sample was correctly and uniformly applied to the absorbent.
Yet another object of the invention is to provide a method which can be made and utilized at a low cost.
Yet another object of the invention is to provide a method which assists in avoiding the need to take repeat samples from subjects due to improper sampling procedures.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention.